Pathological changes in primary cilia: A novel mechanism of graft cholangiopathy caused by prolonged cold preservation in a rat model of orthotopic liver transplantation

Abstract

To study the impairment of cholangiocyte primary cilia caused by prolonged cold preservation and its correlation with graft cholangiopathy after orthotopic liver transplantation (OLT). Subjects were 60 male Wistar rats that were divided into 2 groups: a control group (n = 30) receiving a donor liver preserved for 1 h and a study group (n = 30) receiving a donor liver preserved for 12 h. A two-cuff method was used to establish the OLT model, and the hepatic artery and bile ducts were reconstructed using stents. Samples were collected 2, 8, and 16 weeks after surgery, and 5 samples were collected from each group at each time point. Serum biochemical indicators were measured, morphological changes in intrahepatic bile ducts and cholangiocyte primary cilia were observed using an optical microscope and scanning electronic microscope, respectively, and the ciliary marker (α-tubulin) and membrane proteins (PC-1, TRPV4, and P2Y12) were detected using immunofluorescence analysis and Western blotting. In the study group, phlogocytes infiltrated around bile ducts and bile ducts proliferated markedly at 8 weeks. At 16 weeks, the biliary structures were indistinct and some bile ducts disappeared, a large amount of collagen was deposited, numerous phlogocytes infiltrated around ducts, some biliary epithelial cells (BECs) were deformed or dead, and primary cilia disappeared. In the control group, the intrahepatic bile ducts and BECs were nearly intact and the primary cilia were present. In the study group, the expression of α-tubulin, polycystin-1 (PC-1), TRPV4, and P2Y12 in bile ducts disappeared completely after 8 weeks. In the control group, expression of the marker and proteins decreased at 2 weeks and increased slightly after 8 weeks. These results suggest that the study group had dysfunctional primary cilia at the start of OLT and that this dysfunction was irreversible. In the control group, the primary cilia defects and subsequent biliary injury were temporary. Thus, prolonged cold preservation of a donor liver may cause graft cholangiopathy by altering the integrity and functions of cholangiocyte primary cilia.